US Bridges

US 21 SB over Whale Branch

Fair

Beaufort County, South Carolina · 8.7 MI NW of Beaufort · Structure no. 000000000005219

Built
1968
57 years old
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
950 ft
4 main spans
Daily traffic
8,900
2023 count
Owner
State
State Highway Agency

About this bridge

US 21 SB over Whale Branch is a steel stringer/multi-beam or girder carrying US 21 SB over Whale Branch in Beaufort County, South Carolina. It was built in 1968, so it is 57 years old, older than the South Carolina average of 48 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 8,900 vehicles a day, roughly 10% of them trucks, projected to reach 21,983 by 2043. The structure is 950 ft (289.6 m) long and 37 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
CarriesUS 21 SB
CrossesWhale Branch
Location8.7 MI NW of Beaufort
RouteU.S. Route 21
CountyBeaufort County
StateSouth Carolina
Coordinates32.54102, -80.74546
Functional classRural Principal Arterial - Other

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating73.2 US tons
Inventory rating40.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans4 (+11 approach)
Design loadHS 20
Structure length950 ft (289.6 m)
Longest span100 ft (30.5 m)
Deck width37 ft (11.2 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic8,900 (2023)
Projected traffic21,983 by 2043
Trucks10%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was US 21 SB over Whale Branch built?

It was built in 1968, making it 57 years old in 2025.

What condition is US 21 SB over Whale Branch in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in September 2024.

How much traffic does US 21 SB over Whale Branch carry?

About 8,900 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is US 21 SB over Whale Branch?

The structure is 950 ft (289.6 m) long with a longest span of 100 ft (30.5 m) and a deck 37 ft wide.

Who owns US 21 SB over Whale Branch?

It is owned by the State Highway Agency.